Question

Analytical Chemistry

Topic: Spike Recovery

Question: Explain why a recovery significantly greater than 100% or significantly less than 100% is possible.

Answer #1

Significantly greater:

- Due to humidity and human/methodology errors

i.e.

% X = mass of X / total mass * 100%

if initial "total" mass was 10.5 g

and we recovered 10.6 g, then, clearly X has extra mass, i.e. humidity of other compounds

- Less than 100%: since method/nature will not allow us to obtain 100% fro the product

example:

extraction of A in water/ether extraction

A will always remain in water + ether... so recovery of 100% of A in water will be impossible

Explain briefly why recrystallization can never result in 100%
mass recovery even if you used pure material. Also explain why mass
recovery is greater if you cool to 0 degrees C rather than room
temperature.
Explain very briefly why mass recovery is reduced if you use an
excess amount of boiling solvent and why washing product crystals
with excessive amounts of solvent especially warm solvent can
result in reduced mass recovery.

f) If amount1 is greater than 10 and amount2 is less than 100,
display the greater of amount1 and amount2 . Flowchart Code
Fragments (python source code, not Screenshot)

Answer the following question in 100 words or less. Why is
system integration such an important topic in HIT?

For X~N(100, 20) -
40 is greater than or equal to__
60 is greater than or equal to__ of values.
80 is less than or equal to__ of values.

Explain why the entropy of a gas is much greater than the
entropy of a liquid, and why the entropy of a liquid is greater
than the entropy of a solid

Which is more likely, observing a score less than 100, but
greater than 80 sampled at random from a normal distribution with a
mean of 72 and a standard deviation of σ = 20, or a score less than
6 sampled at random from a normal distribution with a mean of 5 and
an unknown standard deviation of σ, and why?

Physical Chemistry- Topic - Raults' Law/Henry's Law/Mole
Factions
Determine which is more poisonous using Physical Chemistry
Two identical glasses filled with 100 mL the same liquid, one
with 1g of NaCl and the other with 1g of iocane powder. Iocane is
colorless, order less, and dissolves isntantly into many
liquids.Iocane is "the most deadly poison known to man". It is not
ionic but has a carbon-iodine bond.
To help you are allowed to only run one test on the two...

Explain why N-15 is greater in marine systems than in
terrestrial systems.

Explain why there are very few counts for energies greater than 700
keV.

Part 1: Provided calculations are performed correctly, would it
be possible to obtain greater than 100% yield for a chemical
reaction? Part 2: Explain/Give a rationale for answer to Part
1.

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